Toothbrushes are well known articles and are generally made of hard plastics materials such as polypropylene, polyamide or styro acryl nitrol (“SAN”), almost invariably by means of an injection moulding process. Two component toothbrushes are also known which comprise parts made of a first material being a hard plastic for example of the type mentioned above, and parts made of a second material different to the hard plastic for example an elastomer (rubbery) material. Suitable thermoplastic elastomers suitable for such two component toothbrushes are well known and are now extensively used. See for example EP-A-0 336 641 and DE-A-39 23 495 for examples of such toothbrushes. Generally such two-material toothbrushes are made in a two stage injection moulding process in which firstly a “skeleton” comprising the first material part(s) is made, and this skeleton is then enclosed in a second injection mould into which the second material is injected. Such a process is well known, and disclosed for example in WO-A-94/05183.
It is also known in the brush industry, e.g. from EP-A-0 742 090 to embed an insert in a brush handle by positioning the insert in the cavity of an injection mould, first covering one side with a injected plastic material, and then in a subsequent injection moulding operation covering the other side with the plastic material. U.S. Pat. No. 2,923,035 discloses a method for making plastic articles, particularly brushes, in which a first piece is first made by injection moulding a first plastic material in a first mould, a second piece of an opaque material is put on top of the first piece, then the assembly of first and second pieces is positioned in a second mould and encased in a second mould, and then encased in a second plastic material.
It is an objection of the present invention to provide a further process for making toothbrushes, and to provide toothbrushes of enhanced appearance, quality and resistance to wear etc., by the use of a third component. Other objects of the invention will become apparent from the following description.